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Hyundai tcu TCU fuse keep blowing when I try to put in in gear. Do I need a new TCU?

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Posted on Jan 02, 2017

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SOURCE: where is the tcu in a 2002 honda accord

it is the Transmission Control Unit. you have to find the reason why the TCU is flashing the D4 fault code. not replace the unit. have your vehicle scanned for another code. your transmission or transaxle is giving you a warning that something is wrong .

Posted on Nov 21, 2008

  • 383 Answers

SOURCE: My Automatic non-turbo 84 300zx wont work

pburcham: In studying up on your problem, I could only come up with a few possibilities from your description.
1. Linkage adjustment
2. A problem with the "Low and reverse Brake band"
however, this usually has a symptom of poor acceleration
due to the transmission slipping. That band has to grab the drum to hold for low gear.
3. Problem with the manual valve in the valve body.
4. Damaged seals causing pressure leakage which will keep the clutches from locking up.
5.Defective "High Reverse clutch" (front) check ball
Possibly a few other things, but everything (unfortunately) is still internal. The inhibitor switch is for the starting circuit and just keeps you from starting the car in anything but park and neutral.
Transmission control unit will not have this harsh an effect. It should operate without the TCU. You should be able to do a manuel shift with the transmission.
Sorry I couldn't be of more help.
I can say one thing, these transmissions were not known for failures, consequently should be a dime a dozen in salvage yards.
Why or how you got a bad one?????? Don't know?
If I can help, let me know........

Posted on Apr 23, 2009

SOURCE: Tranny wont shift from third gear.

You have a solenoid bad in the trans. Will need to drop the pan to replace part. Most likely a code is stored in the computer to help direct the technician.

Posted on Jul 14, 2009

  • 3433 Answers

SOURCE: i have replaced tcu still will not change gears.

Ck the transmission modulator before doing anything else. It's on the back of the trans and operates by a vacuum hose from the engine.**** on it with a vacuum tool and see if it's working. If it fails a vacuum test, Replace it. Theres a rod that goes in it so pay close attention. OR take it to a shop , have the oil and filter changed along with the modulator. That's the safest and easiest thing to do. Do not take it to AAMCO. or the like. Seems they need to overhaul it to tell you if it needed to be overhauled. Good Luck, Ned

Posted on Sep 09, 2009

  • 108 Answers

SOURCE: I have a hyundai starex 99 model...TCU is not

check first any open fuses and wirings leading to the transmission

Posted on Jan 20, 2010

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1 Answer

Tcu fuse 2008 accent keeps blowing

Might be a ground fault which would, of course, cause the TCU circuit to overload. A diaganostic check will find it. The usual cause is a faulty circuit module. but wait for person who knows your year and model to answer. I know of no outstanding electrical problems with that year and model. Honda seems to have the best mechanics, many ASE certified. I love Hondas.

Mar 18, 2013 | Cars & Trucks

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Went to autozone and had checked and computer said faulty tcu and transmission won't shift to third gear or fourth

just delt with this one and found it needed a new transmission the tcu most likly is fine. do you have enough ATF in your transmission.

Jul 05, 2011 | 1997 Dodge Intrepid

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I have a 1992 honda accord dx, i can be in park and the D4 light is on, and the transmission will not shift properly when i put the car in gear, if the light goes out the car runs great, what do you think...

HI. This is a TCU fault. This is intermittently occurring at this time, but it will eventually get worse. You will need to have the TCU scanned for possible transmission trouble codes. I suspect that the TCU will need to be replaced or there may be an issue concerning the solenoid pack. You will need those codes to know for sure.

TCU - Transmission Control Unit

Aug 26, 2010 | 1996 Honda Accord

1 Answer

Tranny wont shift from third gear.

You have a solenoid bad in the trans. Will need to drop the pan to replace part. Most likely a code is stored in the computer to help direct the technician.

Jul 14, 2009 | 1991 Dodge Stealth

4 Answers

2001 Hyundai Santa Fe - Engine Code P1602, stuck in gear

Im having the same problem with my 02 Santa Fe. How do i go about fixing this problem? And is it costly? Please help

May 20, 2009 | 2001 Hyundai Santa Fe

1 Answer

What is the selenoid that controls the

I have a solution for you that I know will work, because it has on both of my 1992 Legacy wagons, but first I should explain why your question proceeds from a false assumption. The fuse you mention only exists on vehicles with the 4 speed ecectronically controlled automatic transmission (4EAT)and it asserts "forced front wheel drive mode" by signaling the TCU (transmission contol unit). When the fuse is not inserted the TCU regulates a slip clutch using duty cycle solenoid "C" to optimally adjust the degree of AWD (the front/rear power split) for the present vehicle speed, engine RPM, throttle setting, front and rear driveshaft speeds, and ATF temperature. When the fuse is inserted the TCU allows the clutch to slip freely. The TCU is self diagnosing, and has failure mode fallback strategies. if there duty solenoid C fails, the TCU will always assert AWD withj a 50/50 power split (the clutch is locked when solenoid C fails). The TCU signals failures using the POWER light, much as the CHECK ENGINE light signals errors from the ECU. However, one critical difference is that when a failure is detected, the TCU goes into limp-home mode but illuminate the POWER lamp until the next power-off power-on cycle. (see for details on how to get detailed self-dignostic codes from the TCU without any special tools.)

Subaru service information says that the vehicle should not be driven in forced FWD mode, it is to be used for diagnostic purposes only. (It was provided to allow the vehicle to allow the vehicle be emission tested using a FWD dynamometer. In the USA the dynamometer test requirement was waived for AWD drive before it went into effect.) I don't have a detailed explanation of why, but since duty solenoid C is ON to allow the front/rear clutch to slip, it may fail prematurely if always-on.

Let me begin with the solution and then explain it.- you need to change the transmission filter and fluid, and drain and refill the fron and rear differential fluids. The AT uses simple Dextron II or III (get 2 gallons) and the diffferential both use 80W-90W old fashioned non-synthetic gear oil. You will need roughly 5 quarts for both,

Now for the explanation. When you inserted the fuse and disabled all wheel drive, you eliminated the the center differential action in the AT and the rear differential. When any car turns there is a left-right speed difference,and in an AWD car, there is also a front-rear speed difference. The noise you heard is a symptom of the drivetrain binding up during a turn. There will also usually be noticable lumpy turning moments when the tires jump-slip accomplishing the differential travel, but only on dry pavement. There may also be unpleasant symptoms when accelerating on moderately slick pavement.

You most pressing symptom is caused by the rear differential locking up because of either insuffiicient gear oil, aging gear oil suffering viscosity breakdown, or the wrong gear oil (either synthetic or higher viscosity conventional). The front and rear differentials in the car are limited slip differentials. They rely on the properties of 80-90W gear oil properly filled and in good condition.

Because its connected to the engine heat, the front differential oil will be in worse condition than the rear, and you would probably find that only draining and refilling the rear makes a big difference, but not enough or the problem comes back in a few weeks. When you put it in FWD only mode putting all the power is in the front, it has more incentive to slip, masks the problem temporarily.

You also need to change the ATF filter and drain and fill the AT because the center (front-rear) differential action is accomplished in the AT, and the problem will only resurface for that reason as well. The conventional ATF in these transmissions begins to suffer viscosity breakdown in as little as 10,000 miles and since no one changes the ATF and filter in an aging car afer you drain it you should drop and clean the AT pan and change the filter and gasket. It would be all but impossible not to strip the threads in the aluminum housing putting the rusted screws back in. (they pass through the flange and the tips corrode). Buy new screws at the hardware store and put then in with blue threadlocker. Be careful not to overtighten, but if one strips use heli-coil inserts to make thread repairs.

Apr 05, 2009 | 1991 Subaru Legacy

1 Answer

Hello, I own a 93 toyota forerunner, 4*4, v6, automatic. Transmission was only shifting at very high rpms. Replaced trans with another out of identical vehicle, transmission will not shift, disconnected...

The transmission is controlled by the Transmission Control Unit (TCU).

Throttle position, rpm, and speed are input parameters to the TCU. The TCU has a default set of shift patterns. These shift patterns change over time based on your specific vehicle setup and driving habbits.

The shift patterns are only slightly affected by driving habbits over many driving cycles. But, changing the relationship between the throttle position and the actual speed being reported by the speed sensor can have an immediate effect on shift patterns.

While your speedo may now be correct, the realtionship between rpm and thottle position has not been corrected. That would take a gear change in the differentials.

The TCU can be reset to an inital learn base line. When this is done, the TCU will instantly learn the dynamics of your setup.

Any shop with an advanced ODB scan tool can reset the the TCU. The dealer or a transmission shop would be preferable.

You really should change your differential gears as opposed to resetting the TCU

This information was posted by ftgiles here

Jan 06, 2009 | 1993 Toyota 4Runner

1 Answer

Where is the tcu in a 2002 honda accord

it is the Transmission Control Unit. you have to find the reason why the TCU is flashing the D4 fault code. not replace the unit. have your vehicle scanned for another code. your transmission or transaxle is giving you a warning that something is wrong .

Nov 20, 2008 | 1992 Honda Accord

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